Most fragrance chemicals are hydrophobic materials indicating that they are more soluble in non-aqueous based systems than aqueous systems. For this reason, fragrance compositions are commonly provided in a hydrocarbon base. These hydrocarbon bases comprise materials including alcohols, such as ethanol, and other materials, such as dipropylene glycol and diethyl phthlatae and isopropyl myristate. Higher boiling solvents can also be used in systems depending on the application and are commonly provided in a non-aqueous based systems. Higher temperature applications include plug-in air fresheners where the electric power source can be used to power a heating element to deliver the fragrance chemicals and a higher boiling fragrance solvents. In these situations higher boiling point carriers such as dipropylene glycol ethers are often used as the fragrance chemical solvents.
Alternatively, an aqueous based system may be employed to deliver fragrance materials. One advantage of an aqueous based fragrance system is the reduced flash point of the fragrance system. In order to make the fragrance chemicals miscible and deliverable in the aqueous system, surfactant and other chemicals are used. For example, U.S. Pat. No. 6,238,646, the contents hereby incorporated by reference, discloses the use of a polymeric emulsion with a dispersed oil phase for the deliverance of atomized oil, such as a fragrance oil, insecticidal oil or medicinal oil. The patent states that the dispersed oil has the benefits of not needing to be shaken before use, is not flammable and does not deposit fragrance on surfaces.
The deposition of fragrance on surfaces is a problem with many fragrance systems. Controlling the rate of fragrance usage, the particle size of the fragrance as well as insuring that the fragrance remains in the atmosphere is critical. In particular for air fresheners, it is critical that the fragrance not deposit on surfaces such as tables and other surfaces leaving unsightly appearance or damage surfaces.
Despite the teachings, there is an ongoing need for new fragrance compositions that deliver the desired fragrance in a safe manner that does not deposit fragrance on surfaces after use.